Present Ecological Status and Diversity of Zeuxine Lindl. a Botanically Less Known Orchid of Dibrugarh District of Assam, North East India

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1 International Journal of Plant Research 2012, 2(5): DOI: /j.plant Present Ecological Status and Diversity of Zeuxine Lindl. a Botanically Less Known Orchid of Dibrugarh District of Assam, North East India Khyanjeet Gogoi 1,*, R. L. Borah 2, Raju Das 3, Rajendra Yonzone 4 1 Daisa Bordoloi Nagar, Talap, Tinsukia, , Assam, India 2 Dept. of Botany, DHSK College, Dibrugarh, , Assam, India 3 Nature s Foster, P.Box 41, Shastri Road, P.O. Bongaigaon, , Assam, India 4 Dept. of Botany, St. Joseph s College, P.O. North Point, District Darjeeling, W. B., , India Abstract Assam is the second largest state of North-East India and treasure trove of Indian orchids. Dibrugarh District is in the located in the eastern part of the state with rich native orchid species. This report is the outcome of our intensive field studies carried out during We have chosen opportunistic method to cover all representative areas of different habitat. We have surveyed the area covering all the seasons of the year. For microhabitat structure randomly selected quadrat of 5mx5m were laid in the field and noted down all the features. In this study a total of 114 Orchid species under 54 genera have been recorded from the district. The study revealed 29 species as terrestrial and the rest 85 species are epiphytic. Among the terrestrial genus Zeuxine is found as ecologically and taxonomically complex group of Orchidaceae. During this field study, 6 species of the genus Zeuxine were recorded viz. Z. clandestine; Z. glandulosa; Z. goodyeroides; Z. longilabris; Z. nervosa and Z. Strateumatica. The present study envisages the threat and status of these species with conservation recommendation. Moreover, this is the first attempt to establish the taxonomic identification to workout currently accepted botanical names of the genus with its ecological status, voucher specimen numbers, habitat, phenology and distribution in this district. Keywords Zeuxine, Present Status, Diversity Resources, Dibrugarh District, Assam 1. Introduction Zeuxine is an annual terrestrial or rarely lithophytic herbs. The plant usually have elongate, creeping, fleshy rhizo me with several nodes. The root is cy lind ric and stout, that eme rge out fro m these nodes. Stem erect or ascending, terete, leafy and glabrous. Leaves cauline or sub-rosulate, adaxially green to blackish, sometimes with a white stripe along midvein, linear-lanceolate, obliquely ovate-lanceolate, or elliptic, with or without a petiole-like base, sheathing stem, sometimes slightly fleshy. Inflorescence glabrous or pubescent, with a few crowded to scattered sheathing bracts and a few or many flowers in a short to elongate terminal raceme. Flowers resupinate or erect, small, not opening widely; ovary twisted, glabrous or pubescent. Sepals free, similar, outer surface glabrous to pubescent; dorsal sepal concave, forming a hood with petals; lateral sepals enclosing base of lip. Petals connivent with dorsal sepal, nearly as long as dorsal sepal though usually narrower; lip usually adnate to column margin at base. Column short, dilated; anther ovoid, * Corresponding author: khyanjeetgogoi@gmail.com (Khyanjeet Gogoi) Published online at Copyright 2012 Scientific & Academic Publishing. All Rights Reserved 2-locular; pollinia 2. Capsule erect. The genus Zeuxine is a taxonomically complex group of Orchidaceae, established in the year 1826 by John Lindley in the appendix to his Collectanea Botanica. About 80 species are generally distributed in the tropical and South Africa, through tropical and subtropical Asia, to New Guinea, NE Australia, and the SW Pacific islands and China Study Area Dibrugarh District is located in eastern part of Assam, India, with an area of 3381 sq. km. The district extends from 27 5 N to N latitude and E to E longitude. It is bounded by Dhemaji district on the north, Sivasagar district on the south, Tinsukia district on the east and Lakhimpur district on the west. The area stretches from the North bank of the mighty Brahmaputra river, which flows for a length of 95 km. through the northern part of the district to the Patkai foothills in the south. At the foothills the altitude is 200m MSL and the Burhidihing river bank is 99m MSL. The area under forest in this district is hectares. Among the protected areas, there are five reserve forests in the district, namely Joypore with hectares[10, 11], Jokai with hectares[2], Namdang

2 161 International Journal of Plant Research 2012, 2(5): with hectares, Telpani with hectares and Dih ingmu kh with hectares. The Joypur Reserve forest forms a part of the world heritage of tropical/sub-tropical wet evergreen forest, classified as 1B/CI[4]. The multi layered canopy of the forest is rich in both floral and faunal biodiversity. Considering the vegetation type this forest is known as the only Rain forest in the state. This forest is great reservoir of orchid germplasm due to its high rainfall, relative humidity and light penetration[10, 11]. Among the other forest areas Jokai, Namdang, Telpani and Dihingmukh are having mixed forest with evergreen patches, typified as 3/152 and 4D/SSI[4]. All these forests are close to the bank of river Buridihing or touching it Cli mate Dibrugarh District has unique physiographic elements, the area experiences subtropical monsoon climate with mild winter, warm and humid summer. The maximum rainfall is in summer (2740mm-3640mm) and the minimum rainfall is during winter (430mm-700mm). The maximum te mperature ranges between 33 to 37 and minimum temperature between 8 to 10. The climate can be d istinctly classified into four seasons i.e. Winter, set in the November and lasts upto January followed by Pre- Monsoon period From March to May, when temperature start rising; Monsoon sets during June-July and lasts upto to August September and Retreating monsoon that starts from last week of September or first week of October the monsoon starts retreating until winter arrives. 2. Materials and Method The intensive field survey work was carried out during covering all the seasons of the year in all parts of forest areas of Dibrugarh district of Assam. In each of the forest areas we used quadrat method to enumerate the habitat. For the diversity of the species we preferred the opportunistic method according to the habitat criteria. Moreover, during this study we have used pre-designed datasheet covering all the parameters like humidity, light intensity, as well threats and micro habitat. We have collected the specimen with flowers and mounted it into herbariu m following standard methodologies of Jain & Rao[14]. We have taken extra care to photographs the live species in field with its habitat. From the collected specimen we have drawn the sketches and describe them following standard protocol of taxonomic description. During the field study we have noted down the phenophases of all the species encountered. The collected samples were compared and consulted with the publication on local, national and international floras like Orchid Flora of KamrupDistrict[1]; The genera and species of Orchidaceous plants[18]; Folia Orchidacea[17]; The orchids of the Sikkim Himalayas[15]; A Guide to the Orchid of Sikkim[3]; The Orchids of Thailand[24]; The Orchid Flora of North-West Himalaya[9]; Indian Orchids Guide to Identificationand Culture[22]; Orchids of Mussoorie[23]; Orchids of Arunachal Pradesh[12]; Flora of British India[13]; Orchids of Kumaun Himalaya[20]; A Catalogue of Indian Orchids[16]; Orchids of Nagaland[8]; Orchidaceae of Arunachal Pradesh[6]; Orchid Flora of Arunachal Pradesh[5]; 100 Sikkim Himalayan Orchids[21]; Orchids of India[19]. Specimens were matched at the herbarium of department of Botany Gu wahati University and Botanical Survey of India, Eastern Circle, Shillong (Assam herbarium). Finally all the Voucher specimens have been deposited in the Herbaria of department of Botany, Guwahati University. All the species were arranged systematically with botanical names, habitat, local distribution and flowering month. For study of the microhabitat, randomly selected quadrat of 5mx5m were laid in the field. 3. Results and Discussion The climatic condition of Dibrugarh district of Assam of North East India is most congenial for the lavish growth and development of wide varieties of Orchid species in natural habitat. During the field surveys, six species of Zeuxine were recorded. Among these Z. glandulosa is found to be endangered and new report for Assam, and other species viz., Z. clandestine and Z. longilabris is endangered, Z. nervosa is vulnerable, Z. goodyeroides and Z. strateumatica are found in abundant throughout the district. It is observed that the genus Zeuxine grow well in humus rich soil and shady places and some species grow well in grassland. The undisturbed forest habitat is found ideal for its lavish growth and development. The genus is not only ecologically important but due to their small beautiful flowers it also has immense floricultural importance too. But the rampant destruction of forests causing greater harm in the natural population of this botanically less known beautiful Orchid Zeuxine in the state of Assam. Key to the species 1a. Leaves linear to linear-lanceolate, not stalked, base directly sheathing stem...6. Z. strateumatica 1b. Leaves ovate-lanceolate to oblonglanceolate, base contracted into a petiole-like stalk sheathing stem. 2a. Leaves blackish- purple, oblonglanceolate.2. Z. glandulosa 2a. Leaves not blackish- purple, ovatelanceolate. 3a. Co lu mn with lamellate wings. 4a. Epichile of lip transversely dilated but as broad as or narrower than hypochile, entire to shallowly 2-lobed Z. goodyeroides 4b. Epichile of lip dilated, broader than hypochile,

3 Khyanjeet Gogoi et al.: Present Ecological Status and Diversity of Zeuxine Lindl. a Botanically 162 Less Known Orchid of Dibrugarh District of Assam, North East India distinctly 2-lobed Z. nervosa 3b. Column without any appendage. 5a. Lip toothed on the outer margin, mid lobe 2- winged, elongate Z. longilabris 5b. Lip not toothed on the outer margin, sessile, base saccate, enclosing a simple and conical callus on either side Z. clandestine Enumeration Zeuxine clandestina Blu me, Coll. Orchid ; Barua, Orch. fl. Kamrup Dist ; Mishra, Orch. India Plant 10 15cm tall, stems and peduncles glabrous. Leaves 2 4, 3 4 2cm, linear, glabrous, 3 nerved, sheathed, scarious. Inflorescence spikes, 8 10 flowered. Flowers completely resupinate, sessile, pin kish-white; sepals with prominent midrib, puberulous, pinkish. Dorsal sepals ovate, obtuse, mm; lateral sepals ovate lanceolate, broadly acute, mm. Petals mm, dimidiate, obliquely ovate, narrowed at base, obtuse, white. Lip mm, sessile, base saccate, enclosing a simple and conical callus on either side; Column without any wing or appendage. Pollinia pyriform, granular. Voucher specimen: Gogoi et al., Flowering: January- March. Local distribution within Dibrugarh district: Jeypore. Present ecological status: Endangered.[Figure 1.] middle part curved inwards and white; the interior of sac with row of 3 lamellate calli on each side and an incurved conical tooth on each margin, 0.5 cm long. Column with very large lamellate wings at base, porrect, incurved; rostellum projecting, broad. Pollinia pyriform, bifid, groved; stigmas 2, small, linear- oblong. Figure 2. Zeuxine glandulosa King & P ant ling Voucher specimen: Gogoi et al., Flowering: March- April. Local distribution within Dibrugarh district: Jeypore. Present ecological status: Endangered.[Figure 2.] Zeuxine goodyeroides Lind l. Gen. Sp. Orchid ; Hook. f., Fl. Brit. India 6: Plant 15 27cm tall, sheaths cm, clasping. Leaves 3 5, cm, oblong-ovate, acute, shortly petiolate. Inflorescence laxly many flowered, 4 10cm long, ridged, sparsely pubescent, with 1 or 2 linear-lanceolate sheaths. Flowers 5 6mm long, pink-white, lateral sepals green; pedicellate-ovary sessile, 6 8mm long. Sepals subsimilar; dorsal sepal 3.9 5mm long, ovate, acute; lateral sepals mm, narrowly lanceolate, spreading. Petals 3.9 5mm long, white, falcate, subacute, connivent. Lip 3.9 5mm long, basally saccate, bidentate within; apex small, with incurved margins. Column 3 3mm, broad, margins winged below. Pollinia clavate; stigmas oval, lateral. Figure 1. Zeuxine clandestina Blume Zeuxine glandulosa King & Pantling in Ann. Roy. Bot. Gard. (Calcutta) 8: 288. t ; Pradhan, Indian Orchid-I: ; Mishra, Orch. India Terrestrial, 5 20 cm high. Leaves oblong lanceolate, acute, shortly petiolate, cm, blackish- purple; petiole expanded into a wide hyaline sheath. Inflorescence laxly few flowered; peduncle short, pubescent; rachis densely glandular- pubescent, cm long. Flowers 0.5 cm long olivegreen, column and central contracted part of lip white. Sepals connivent, subsimilar, ovate, acute, subequal, sparsely glandular-pubescent, 0.5 cm long. Petals asymmetrically suborbicular, suboblique, apiculate, 0.5 cm long. Lip about as long as the sepals, widely saccate at base, Figure 3. Zeuxine goodyeroides Lindl

4 163 International Journal of Plant Research 2012, 2(5): Voucher specimen: Gogoi et al., Flowering: Junuary- February. Local distribution within Dibrugarh district: Jeypore. Present ecological status: Common.[Figure 3.] Zeuxine longilabris (Lindl.) Trimen, in Joour. Ceylon Br. Roy Asiat. Soc. 9: 90. I885; Hook. f., Fl. Brit. India 6: ; Chowdhery, Orch. Fl. Arunachal Prad Plant 15 20cm tall. Leaves cm, ovate to ovate-oblong, acute, 5 7 nerved, drooping, copper-brown white, shortly petioled. Inflorescence terminal, fewflowered, 2 6cm long, glandular-pubescent racemes on elongate, slender, purple scapes. Flowers greenish-white; sepals green, broad, obtuse, pubescent. Dorsal sepal deltoid-ovate, obtuse, 6 2mm; lateral sepals falcately oblong mm. Petals appressed to the dorsal sepal, falcately oblong, white, 6 2mm. Lip wh ite, longer than the sepals, 11mm long; mid lobe 2- winged, elongate, toothed on the outer margin. Column without any appendage. Pollinia pyriform, clavate. Habitat: Terrestrial, growing in grass land. Voucher specimen: Gogoi et al., Flowering: March -May. Local distribution within Dibrugarh district: Jeypore. Present ecological status: Endangered.[Figure 4.] Figure 4. Zeuxine longilabris (Lindl.) Trimen Zeuxine nervosa (Wall. ex Lindl.) Benth. ex Trimen, J. Ceylon Branch Roy. Asiat. Soc. 9: Plants cm tall, slender, 3 6-leaved. Leaves clustered at stem apex, not usually withering at anthesis, ovate to ovate-elliptic, cm, apex acute. Inflorescence cm, with 2 or 3 widely spaced sterile bracts, sparsely villous, many flowered. Flowers fragrant, resupinate, weakly spreading, small. Sepals reddish brown to yellowish green, glabrous; dorsal sepal ovate, concave, mm, apex acute or subacuminate; lateral sepals oblong-ovate, mm, apex acute to obtuse. Petals white, ovate, oblique, mm, glabrous, apex obtuse; lip white or pale yellow, Y-shaped. Column 2.2 mm; wings prominent, broadly triangular. Habitat: Damp places in forests. Voucher specimen: Gogoi et al., Flowering: January-March. Local distribution within Dibrugarh district: Jeypore. Present ecological status: Vulnerable.[Figure 5.] Figure 5. Zeuxine nervosa (Wall. ex Lindl.) Benth. ex Trimen Zeuxine strateumatica (Lindl.) Schlechter in Engler, Bot. Jahrb. 45: ; Chowdhery, Orch. Fl. Arunachal Prad ; Barua, Orch. fl. Kamrup Dist Plants 4 24cm tall, slender, erect, leafy. Leaves cm, cau line, usually clustered and overlapping, pale brown, linear to linear-lanceolate, base directly sheathing stem, apex acuminate. Inflorescence 2 7cm long, glabrous, with a few to more than 20 densely arranged flowers. Flowers mm, resupinate, white or pale purple white, small. Sepals glabrous; dorsal sepal mm, narrowly ovate-oblong, concave, 1-veined, apex obtuse; lateral sepals mm, obliquely oblong, 1-veined, apex acute or obtuse. Petals mm, subovate to obovate, oblique, glabrous, 1-veined, apex obtuse. Lip 4 5mm long, pale yellow to yellow, cymbiform, 3- partite. Column 1.5mm long; wings longitudinally oblong. Habitat: Terrestrial, growing in grass land. Voucher specimen: Gogoi et al., Flowering: January-March. Local distribution within Dibrugarh district: Namdang, Telpani and Dihingmukh. Present ecological status: Common.[Figure 6.] Figure 6. Zeuxine strateumatica (Lindl.) Schlecht er

5 Khyanjeet Gogoi et al.: Present Ecological Status and Diversity of Zeuxine Lindl. a Botanically 164 Less Known Orchid of Dibrugarh District of Assam, North East India 4. Conclusions There was little information on the taxonomic and ecological status of Zeuxine in Assam. This study enable to fill the gap for its proper taxonomic treatment in local flora. Moreover, the conservation of this species is considered as major priority. For conservation of orchid species the habitat need to be conserve. But due to socio political condition in the past few decades and illegal tree felling, large scale destruction of forests has been resulted in a drastic depletion of Orchid species diversity in Dibrugarh district. In this regard, we consider both short term and long term conservation for the orchid species involving both government and non-government agencies. As it was revealed that deforestation has severely affected the biodiversity of Orchids, it is therefore desirable to conserve the precious Orchid flora of this region through ex-situ as well as in-situ conservation methods. The government and non-government organisation must work with individual communities in the fringe to improve the habitat of orchids in the area. An atmosphere of conservation contagion should be developed around the protected reserve forest areas and community conservation groups could be formed to join the conservation activities. By conducting village level awareness programmes by government departments and NGOs with constant affiliation with department of forest and wildlife in the regions is the only solution to save our praiseworthy Orchid diversity resources of Dibrugarh district. ACKNOWLEDGEMENTS We are very much gratefu l to Mr. Dinesh Valke, for allowing us to use his photographs of Zeuxine longilabris for this study. We are gratefu l to Dr. G.C. Sharma, Dept. of Botany Guwahati University, Assam and Department of forest, Dibrugarh, Assam for constant supervision and valuable suggestions during the course of present studies. REFERENCES [1] Barua, I.C, Orchid Flora of KamrupDistrict. Bishen Singh Mahendra Pal Singh, Dehra Dun India, [2] Borah, R. L., Gogoi, K. & Sharma, G. C. A Taxonomic Survey of the Orchid Diversity of Jokai Reserve Forest of Dibrugarh District of Assam, India. Journal of Non- Timber Forest Products, 2010, 17(1): [3] Bruhl, Paul, A Guide to the Orchid of Sikkim. Thacker & Spink & Co., Simla, India, [4] Champion, H.G. Seth, S.K, A revised study of the forest type of India, Govt. Of India Press, Nasik, India, [5] Chowdhery, H.J, Orchid Flora of Arunachal Pradesh. Bishen Singh Mahendra Pal Singh, Dehra Dun, India,1998. [6] Chowdhery, H.J. Pal, G.D, Orchidaceae of Arunachal Pradesh. Bishen Singh Mahendra Pal Singh, Dehra Dun, India, [7] Chowdhery, S, Assam s Flora. Assam Science Technology and Environment Council, Guwahati, Assam, India, [8] Deorani, S.C. Naithani, H.B, Orchids of Nagaland. Oriental Enterprises, Dehra Dun, India, [9] Deva, Som & H. B Nathani, The Orchid Flora of North-West Himalaya. Bishen Singh Mahendra Pal Singh, Dehra Dun, India, [10] Gogoi, K., Borah R.L. Sharma, G.C, Additions to the Orchid flora of Joypur Reserve Forest in Dibrugarh district of Assam, India in: Pleione, 2011, 5 (1): [11] Gogoi, K.; R. L. Borah & G. C. Sharma, Orchid flora of Joypur Reserve Forest of Dibrugarh district of Assam, India, in: Pleione, 2009, 3(2): [12] Hegde, S.N, Orchids of Arunachal Pradesh. Govt. of Arunachal Pradesh, Itanagar, India, [13] Hooker, J.D, Orchidaceae. In: Flora of British India. L. Reeve and Co., Ashford, Kent. & VI: 1890, [14] Jain, S.K. Rao, R.R, A Handbook of Field & Herbarium methods. Today & Tomorrow s Printers & Publishers, New Delhi, [15] King, G. Pantling R. The orchids of the Sikkim Himalayas. Annals of the Royal Botanical Garden Calcutta 8: 1898, [16] Kumar, Sathish. Manilal, K.S, A Catalogue of Indian Orchids. Bishen Singh Mahendra Pal Singh, Dehra Dun, India, [17] Lindley, J, Folia Orchidacea An enumeration of the known species of Orchids, London, [18] Lindley, J, The genera and species of Orchidaceous plants. London, [19] Misra, S, Orchids of India. Bishen Singh Mahendra Pal Singh, Dehra Dun, India, [20] Pangtey, Y.P. S., S. S. Samant, G.S. Rawat, Orchids of Kumaun Himalaya. Bishen SinghMahendra Pal Singh, Dehra Dun, India, [21] Pradhan, M, 100 Sikkim Himalayan Orchids, Mumbai, India, [22] Pradhan, U.C, Indian Orchids Guide to Identificationand Culture. Bharat Lithographing Co.Calcutta, India. Vol- I, [23] Raizada, M.B., H.B. Naithani. H.O. Saxena, Orchids of Mussoorie. Bishen Singh Mahendra Pal Singh, Dehra Dun, India, [24] Seidenfaden, G, The Orchids of Thailand, Vol.I- IV. The Siam Society, Bangkok, 1962.